1. Field of the Invention
The present invention relates to a building material such as a siding board.
2. Description of the Related Art
A ceramic siding board, a metal siding board, an ALC board (Autoclaved Lightweight aerated Concrete board), and the like are used as building materials constituting the exterior walls and the interior walls of buildings.
In recent years, there has been an increasing need for the above-described building materials to have a high-quality appearance. As one measure to meet this need, mirror finish on the surface of the building materials has been examined.
JP 2006-181492A discloses a method of forming a finished layer in the following manner. First, a polyester surfacer is applied to the surface of a base material to form an underlayer, onto which a polyester black enamel paint is then applied to form a middle coat layer. Then, a polyester clear paint is applied to the upper surface of the middle coat layer. After being cured and dried, the coating of the polyester clear paint is polished to form a finished layer. In this method, the middle coat layer is formed by multiple spray applications at substantially equally-spaced time intervals, and the finished layer is formed by spray applications at substantially the same time intervals. With this method, the clear paint constituting the finished layer contains no pigment, and therefore, clogging of a coated abrasive is prevented during polishing, and the subsequent polishing using a cotton buff or the like renders the surface dense and flat, making it possible to perform high-quality burnished mirror finish.
In general, building materials such as a ceramic siding board are stacked for storage or transportation, as described in JP 2010-58846A.